First, a Ficus does not handle the freeze we get every so often so I don't recommend those to my clients. The Sisso is a good fast growing shade tree and the roots are not invasive as long as they are deep watered just like any other tree should be. The main thing is to have all trees on their own drip line(separate from the plants) Watering trees on the same line as the plants will result in the roots staying near the surface.

How 'bout Chinese Pistache? They seldom exceed 30 feet here in the desert, have beautiful fall foiage colors and provide great shade.

You could also try Thornless Honey Mesquite. It has large compound leaves and a graceful, weeping form. Also matures to about 20 x 30 feet. I have the 'Maverick' cultivar and love it.

Here is a link that might be useful: Thornless Honey Mesquite

I agree with dirtydoug. the sissoos are not as invasive as people make them out to be. sure, if you plant it shallow and next to a lawn that gets frequent shallow waterings, good luck with that, but if you plant it just a bit deeper and deep water it by making a berm around it and flooding it, it grows just fine. The posting I've seen where they call sissoo the "tree from hell" because of suckers is just pure BS. Maybe they're on a flood irrigated lot or use drip watering, or lawn sprinklers, but I have not had any problems with mine and it's a great shade tree.